Teeth grinding (particularly while asleep) is a common problem. Sufferers can wake-up with sore teeth or an aching jaw and their partners frequently complain about the sound that it makes. Constant teeth grinding causes sufferers to build up their masseter muscle, often making their jaw look square in shape. Muscle relaxant (or ‘anti-wrinke’) injections can be used to successfully treat the condition, medically referred to as Bruxism. The treatments works by relaxing the masseter muscle and is the same technique used to reduce the squareness of the jawline.